海洋地质前沿2025，Vol.41Issue(6)：40-53,14.DOI:10.16028/j.1009-2722.2024.049
南海北部李春海山多金属结核的成因类型及其物质来源探讨
Genetic types and material sources of ferromanganese nodules in the Lichun Seamount of the northern South China Sea
摘要
Abstract
Although previous studies have been conducted in great detail on oceanic ferromanganese nodules,re-search on those nodules on seamounts in the marginal sea slope remains relatively insufficient.In this study,ferro-manganese nodules were sampled from the Lichun Seamount in the northern slope of the South China Sea for re-search.Comprehensive analytical techniques were applied,including XRD mineralogy,LA-ICPMS in-situ major and trace element geochemistry,and layered isotope geochemistry,and the origination of the ferromanganese nod-ules was investigated.Results reveal that the ferromanganese nodules have four distinct layers with unique miner-al compositions,reflecting different hydrodynamic conditions and terrigenous input rates during their growth.The nodules are mainly composed of vernadite,quartz,and plagioclase.However,in addition to vernadite,the man-ganese-phase minerals in layers 3 and 4 also contain birnessite and todorokite,suggesting their diagenetic origin.The results of principal component analysis indicate that the ferromanganese nodules are characterized by multi-stage and multi-source mineralization indicated by the formation of iron-phase minerals and the growth of man-ganese-phase minerals.The Mn/Fe ratio was less than 2.5 mostly,while at a few points in layers 3 and 4,it was above 2.5 or even exceeded 5.The REY partition pattern of the nodules displayed a strong positive Ce anomaly,and most of them were mirror-symmetric with the South China Sea seawater.The REY partition pattern at a few detection points in layers 3 and 4 were similar to that of the sediment pore water.The Sr-Nd isotope values were between the South China Sea seawater and sediment but closer to the seawater,and the Pb isotope exhibited the characteristics of Taiwan Island source.Therefore,the ferromanganese nodules were mainly of hydrogenetic ori-gin,with a small number of diagenetic components added in the later growth stage.The materials were originated from the surrounding seawater and affected by terrigenous material input from Taiwan Island.关键词
南海北部/李春海山/多金属结核/水成成因/陆源物质Key words
northern South China Sea/Lichun Seamount/ferromanganese nodule/hydrogenetic origin/terrigen-ous material分类
海洋学引用本文复制引用
李伟,许丞,王先庆,黄赞慧,刘维亮,钟云,蔡砥柱,邢子浩,孟庆杰,鲁旭,李奇,陈治国..南海北部李春海山多金属结核的成因类型及其物质来源探讨[J].海洋地质前沿,2025,41(6):40-53,14.基金项目
自然资源综合调查指挥中心科技创新基金(KC20240019) （KC20240019）
中国地质调查局项目(DD20230413,DD20211554) （DD20230413,DD20211554）
广东省基础与应用基础研究基金(2024A1515010439) （2024A1515010439）
国家自然科学基金(41972049) （41972049）
